Electrical switch

Abstract

An electrical switch has a casing, fixed contacts and at least one moving contact located in the casing, and a rotor supported in the casing for rotation about an axis of rotation to move the moving contact into and out of contact with at least one of the fixed contacts. There is also an operating mechanism for rotating the rotor. The fixed contacts are arranged on one side of the rotor with respect to the axis of rotation.

The invention claimed is: 
     
       1. An electrical switch comprising:
 a casing; 
 a plurality of fixed contacts and at least one moving contact located in the casing; 
 a rotor supported in the casing for rotational advancement about an axis of rotation of the rotor to move the moving contact into and out of contact with at least one of the fixed contacts, thereby performing a switching action, wherein
 the fixed contacts are sequentially arranged along a single straight line that is substantially parallel to the axis of rotation of the rotor, 
 the at least one moving contact is located on and moves with rotation of the rotor, 
 the rotor has a cavity in which the at least one moving contact is located, 
 the cavity has respective open regions through each of which the at least one moving contact is exposed and contactable by a corresponding one of the fixed contacts, and 
 the cavity includes at least one closed region covering and blocking the at least one moving contact from being contacted by the corresponding one of the fixed contacts; and 
 
 an operating mechanism for rotationally advancing the rotor about the axis of rotation of the rotor. 
 
     
     
       2. The electrical switch as claimed in  claim 1 , wherein the fixed contacts are located along the straight line at a regular interval. 
     
     
       3. The electrical switch as claimed in  claim 1 , wherein at least one of the fixed contacts is elongate and extends transverse to the axis of rotation. 
     
     
       4. The electrical switch as claimed in  claim 3 , wherein the at least one fixed contact that is elongate and extends transverse to the axis of rotation has opposite first and second ends and is supported at the first end for pivotal movement at the second end by the rotor. 
     
     
       5. The electrical switch as claimed in  claim 1 , wherein the fixed contacts have substantially the same construction and are arranged in a regular manner. 
     
     
       6. The electrical switch as claimed in  claim 1 , wherein the at least one moving contact extends across all of the fixed contacts for performing switching actions with respective fixed contacts in a plurality of combinations of the at least one moving contact and at least one corresponding fixed contact at different positions of the rotor as the rotor is rotationally advanced about the rotation axis by the operating mechanism. 
     
     
       7. The electrical switch as claimed in  claim 1 , wherein one of the open regions and the one of the closed regions which is associated with the same fixed contact, together, extend circumferentially with respect to the rotor. 
     
     
       8. The electrical switch as claimed in  claim 7 , wherein
 the respective open region and closed region associated with each of the fixed contacts, together, extend circumferentially with respect to a corresponding section of the rotor, and 
 all sections of the rotor are arranged in a row along the axis of rotation of the rotor, with the open regions offset between adjacent sections of the rotor. 
 
     
     
       9. The electrical switch as claimed in  claim 8 , wherein the rotor includes an annular flange extending between and separating adjacent open and/or closed regions. 
     
     
       10. The electrical switch as claimed in  claim 1 , wherein the rotor includes at least one inclined protrusion for abutment by an associated one of the fixed contacts for preventing rotational reversal of the rotor upon release of the operating mechanism. 
     
     
       11. The electrical switch as claimed in  claim 1 , wherein
 the rotor includes at least one inclined protrusion for abutment by an associated one of the fixed contacts for preventing rotational reversal of the rotor upon release of the operating mechanism, and 
 the inclined protrusion extends in the direction of the axis of rotation and on and along an edge of the closed region. 
 
     
     
       12. The electrical switch as claimed in  claim 1 , wherein the cavity has an open end through which the at least one moving contact extends into the cavity. 
     
     
       13. The electrical switch as claimed in  claim 1 , wherein the at least one moving contact has a partially cylindrical body and is fixed to and is coaxial with the rotor. 
     
     
       14. The electrical switch as claimed in  claim 13 , wherein the partially cylindrical body has a cross-section that extends about the rotor over an angle exceeding 180°. 
     
     
       15. An electrical switch comprising:
 a casing; 
 a plurality of fixed contacts and at least one moving contact located in the casing; 
 a rotor supported in the casing for rotational advancement about an axis of rotation of the rotor to move the at least one moving contact into and out of contact with at least one of the fixed contacts, thereby performing a switching action, wherein the fixed contacts are sequentially arranged along a single straight line that is parallel to the axis of rotation of the rotor; and 
 an operating mechanism for rotationally advancing the rotor about the axis of rotation of the rotor and including
 ratchet means in ratchet engagement with a part of the rotor, 
 a manually-operable member for operating the ratchet means in a driving direction for rotational advancement of the rotor, and 
 first resilient means resiliently biasing the ratchet means to return in a non-driving direction that is opposite to the driving direction. 
 
 
     
     
       16. The electrical switch as claimed in  claim 15 , wherein the ratchet means is supported in the casing for linear motion in opposite directions, transverse to the axis of rotation. 
     
     
       17. The electrical switch as claimed in  claim 15 , wherein the ratchet means comprises a ratchet member arranged to engage the part of the rotor in the driving direction, upon operation by the manually-operable member, and to skip the part of the rotor in the non-driving direction under action of the first resilient means. 
     
     
       18. The electrical switch as claimed in  claim 17 , including second resilient means, wherein the ratchet member is pivotable against the second resilient means to skip the part of the rotor in the non-driving direction. 
     
     
       19. The electrical switch as claimed in  claim 18 , wherein the ratchet member includes a rigid support providing rigidity while engaging the part of the rotor in the driving direction. 
     
     
       20. The electrical switch as claimed in  claim 15 , wherein the part of the rotor comprises protrusions annularly arranged on the rotor, around the axis of rotation. 
     
     
       21. The electrical switch as claimed in  claim 20 , wherein the part of the rotor is located at an end of the rotor. 
     
     
       22. The electrical switch as claimed in  claim 15 , wherein the manually-operable member comprises an elongate pliable member connected to the ratchet means. 
     
     
       23. The electrical switch as claimed in  claim 22 , wherein the elongate pliable member is releasably connected to the ratchet means at a junction. 
     
     
       24. The electrical switch as claimed in  claim 23 , wherein the casing has a part which is openable to reveal the junction for connecting and disconnecting the elongate pliable member. 
     
     
       25. The electrical switch as claimed in  claim 15 , wherein
 the casing has, on opposite first and second sides, a plurality of openings, 
 the manually-operable member is exposed for manipulation by a user through a first of the openings that is located in the first side of the casing, and 
 other openings of the plurality of openings are located on the second side of the casing for insertion of electrical cables for connection to the fixed contacts. 
 
     
     
       26. The electrical switch as claimed in  claim 1  wherein the casing has a first compartment holding the fixed contacts and the at least one moving contact, and a second compartment holding the operating mechanism. 
     
     
       27. The electrical switch as claimed in  claim 26 , wherein
 the first compartment is partitioned into separate rooms interconnected by a common area, 
 each room contains a respective fixed contact, and 
 the common area contains the rotor. 
 
     
     
       28. The electrical switch as claimed in  claim 27 , wherein the rooms are oblong in shape and extend in a parallel manner. 
     
     
       29. The electrical switch as claimed in  claim 27 , wherein the rooms have the same shape and size and are aligned with one another. 
     
     
       30. The electrical switch as claimed in  claim 26 , wherein the casing has a first casing part including the first compartment and the second compartment, and a second casing part that closes upon the first casing part. 
     
     
       31. The electrical switch as claimed in  claim 30 , wherein
 the second casing part has an integrally-connected tube through which the manually-operable member extends out of the casing for manipulation by a user, and 
 the tube is externally threaded and co-operable with an internally threaded nut for mounting the electrical switch to an electrical appliance.